Certain engines operating in dusty environments utilize air cleaners of the self-cleaning type. In one arrangement cylindrical cleaner elements are individually and sequentially cleaned by applying a vacuum force or a blowing force to the cleaner element surface; during the cleaning operation either the cleaning nozzle or the cylindrical element is moved in a helical or rotating fashion to cause incremental surface areas of the cleaner element surface to be exposed to the nozzle.
The present invention relates to relatively low cost electric circuitry for controllably energizing the various motors used to perform sequential cleaning of engine air cleaner elements. The circuitry could be used to sequentially operate other load devices.